How to make a charger to charge a 12-volt battery

Written by david sandoval| 13/05/2017

A battery charger can be fabricated from a wall adaptor and battery clamps. (power adaptor image by Sean Gladwell from Fotolia.com)

Twelve-volt batteries are often used to provide electrical energy in automotive applications. Twelve-volt batteries are also used in marine applications, as the filter device in an uninterruptible power supply and as a power source for portable electronics.

To properly maintain a 12-volt battery, the battery must be charged periodically. Trickle-charging is an effective and safe method for charging a 12-volt battery. A simple trickle-charger can be fabricated from a DC adaptor and battery clamps.

Adaptor tips are marked as to which wire constitutes the positive DC connection. (adaptor connectors image by timur1970 from Fotolia.com)

Snip the tip from the adaptor. Pull the wires apart until there is a 6-inch separation between the wire ends. Strip 1/2 inch of insulation from each wire end. Place a piece of electrical tape over the positive wire (which is the wire that formerly connected to the centre conductor on the adaptor tip).

Loosen the retaining screws on the battery clamps. Place the negative wire into the space created by the loosened retaining screw on the first clamp, and tighten the screw until the wire is held firmly. Solder the wire to the retaining screw.

Remove the electrical tape from the positive wire. Place the positive wire into the space created by the loosened retaining screw on the second clamp, and tighten the screw until the wire is held firmly. Solder the wire to the retaining screw.